Rolling Stone co-founder will no doubt jump with joy on the news that Zinio just released a magazine reader app for Android Froyo/Gingerbread smartphones and Honeycomb tablets. The software exposes Android community to some 20,000 digital magazine titles, including National Geographic, Cosmopolitan, Esquire, O, The Oprah Magazine and more. Oh yes, Rolling Stone, too. Sweetening the deal, Zinio is offering most recent issues of two dozen popular magazines free of charge until June 15. And check out this nice perk…